#!/usr/bin/env python
'''
This script generates SRST2 jobs for the Grid Engine (qsub) scheduling system
(http://gridscheduler.sourceforge.net/). It allows many samples to be processed in parallel. After
they all complete, the results can be merged together using SRST2's --prev_output argument.

Thanks to Ramon Fallon from the University of St Andrews for putting this together! Some of the
specifics are set up for his cluster, so modifications may be necessary to make it run properly
on a different cluster using Grid Engine.
'''

import string, re, collections
import os, sys, subprocess
from subprocess import call, check_output, CalledProcessError, STDOUT
from argparse import (ArgumentParser, FileType)
import logging

def parse_args():
	"Parse the input arguments, use '-h' for help"

	parser = ArgumentParser(description='Submit SRST2 jobs through Grid Engine (qsub)')

	# Job details: walltime and memory removed.
	parser.add_argument(
		'--rundir', type=str, required=False, help='directory to run in (default current dir)')

	# SRST2 inputs
	# script argument removed .. mystified by its inclusion, its the main srst2 executable, with the py extension dropped (which is what the modern version of srst2 did)
	parser.add_argument(
		'--output', type=str, required=True, help='identifier for outputs (will be combined with read set identifiers)')
	parser.add_argument(
		'--queue', type=str, required=True, help='name of queue for the marvin cluster)')
	parser.add_argument(
		'--input_se', nargs='+', type=str, required=False, help='Single end read file(s) for analysing (may be gzipped)')
	parser.add_argument(
		'--input_pe', nargs='+', type=str, required=False, help='Paired end read files for analysing (may be gzipped)')
	parser.add_argument(
		'--forward', type=str, required=False, default="_1",
			help='Designator for forward reads (only used if NOT in MiSeq format sample_S1_L001_R1_001.fastq.gz; otherwise default is _1, i.e. expect forward reads as sample_1.fastq.gz)')
	parser.add_argument(
		'--reverse', type=str, required=False, default="_2",
			help='Designator for reverse reads (only used if NOT in MiSeq format sample_S1_L001_R2_001.fastq.gz; otherwise default is _2, i.e. expect forward reads as sample_2.fastq.gz)')
	parser.add_argument(
		'--other_args', type=str, required=True, help='single string (i.e. surround with quotes) containing all other arguments as they would be passed to normal (serial) srst2')

	return parser.parse_args()

def get_readFile_components(full_file_path):
	(file_path,file_name) = os.path.split(full_file_path)
	m1 = re.match("(.*).gz",file_name)
	ext = ""
	if m1 != None:
		# gzipped
		ext = ".gz"
		file_name = m1.groups()[0]
	(file_name_before_ext,ext2) = os.path.splitext(file_name)
	full_ext = ext2+ext
	return(file_path,file_name_before_ext,full_ext)

def read_file_sets(args):

	fileSets = {} # key = id, value = list of files for that sample
	num_single_readsets = 0
	num_paired_readsets = 0

	if args.input_se:
		# single end
		for fastq in args.input_se:
			(file_path,file_name_before_ext,full_ext) = get_readFile_components(fastq)
			m=re.match("(.*)(_S.*)(_L.*)(_R.*)(_.*)", file_name_before_ext)
			if m==None:
				fileSets[file_name_before_ext] = [fastq]
			else:
				fileSets[m.groups()[0]] = [fastq] # Illumina names
			num_single_readsets += 1

	elif args.input_pe:
		# paired end
		forward_reads = {} # key = sample, value = full path to file
		reverse_reads = {} # key = sample, value = full path to file
		num_paired_readsets = 0
		num_single_readsets = 0
		for fastq in args.input_pe:
			(file_path,file_name_before_ext,full_ext) = get_readFile_components(fastq)
			# try to match to MiSeq format:
			m=re.match("(.*)(_S.*)(_L.*)(_R.*)(_.*)", file_name_before_ext)
			if m==None:
				# not default Illumina file naming format, expect simple/ENA format
				m=re.match("(.*)("+args.forward+")$",file_name_before_ext)
				if m!=None:
					# store as forward read
					(baseName,read) = m.groups()
					forward_reads[baseName] = fastq
				else:
					m=re.match("(.*)("+args.reverse+")$",file_name_before_ext)
					if m!=None:
					# store as reverse read
						(baseName,read) = m.groups()
						reverse_reads[baseName] = fastq
					else:
						print "Could not determine forward/reverse read status for input file " + fastq
			else:
				# matches default Illumina file naming format, e.g. m.groups() = ('samplename', '_S1', '_L001', '_R1', '_001')
				baseName, read = m.groups()[0], m.groups()[3]
				if read == "_R1":
					forward_reads[baseName] = fastq
				elif read == "_R2":
					reverse_reads[baseName] = fastq
				else:
					print "Could not determine forward/reverse read status for input file " + fastq
					print "  this file appears to match the MiSeq file naming convention (samplename_S1_L001_[R1]_001), but we were expecting [R1] or [R2] to designate read as forward or reverse?"
					fileSets[file_name_before_ext] = fastq
					num_single_readsets += 1
		# store in pairs
		for sample in forward_reads:
			if sample in reverse_reads:
				fileSets[sample] = [forward_reads[sample],reverse_reads[sample]] # store pair
				num_paired_readsets += 1
			else:
				fileSets[sample] = [forward_reads[sample]] # no reverse found
				num_single_readsets += 1
				print 'Warning, could not find pair for read:' + forward_reads[sample]
		for sample in reverse_reads:
			if sample not in fileSets:
				fileSets[sample] = reverse_reads[sample] # no forward found
				num_single_readsets += 1
				print 'Warning, could not find pair for read:' + reverse_reads[sample]

	if num_paired_readsets > 0:
		print 'Total paired readsets found:' + str(num_paired_readsets)
	if num_single_readsets > 0:
		print 'Total single reads found:' + str(num_single_readsets)

	return fileSets

class CommandError(Exception):
	pass

def run_command(command, **kwargs):
	'Execute a shell command and check the exit status and any O/S exceptions'
	command_str = ' '.join(command)
	print 'Running: {}'.format(command_str)
	try:
		exit_status = call(command, **kwargs)
	except OSError as e:
		message = "Command '{}' failed due to O/S error: {}".format(command_str, str(e))
		raise CommandError({"message": message})
	if exit_status != 0:
		message = "Command '{}' failed with non-zero exit status: {}".format(command_str, exit_status)
		raise CommandError({"message": message})

def check_bowtie_version():
	check_command_versions([get_bowtie_execs()[0], '--version'], 'version ', 'bowtie',
						   ['2.1.0','2.2.3','2.2.4','2.2.5','2.2.6','2.2.7','2.2.8','2.2.9'])

def check_samtools_version():
	check_command_versions([get_samtools_exec()], 'Version: ', 'samtools',
						   ['0.1.18','0.1.19','1.0','1.1','1.2','1.3','(0.1.18 is recommended)'])

def check_command_versions(command_list, version_prefix, command_name, required_versions):
	try:
		command_stdout = check_output(command_list, stderr=STDOUT)
	except OSError as e:
		logging.error("Failed command: {}".format(' '.join(command_list)))
		logging.error(str(e))
		logging.error("Could not determine the version of {}.".format(command_name))
		logging.error("Do you have {} installed in your PATH?".format(command_name))
		exit(-1)
	except CalledProcessError as e:
		# some programs such as samtools return a non-zero exit status
		# when you ask for the version (sigh). We ignore it here.
		command_stdout = e.output

	version_ok = False
	for v in required_versions:
		if version_prefix + v in command_stdout:
			version_ok = True

	if not version_ok:
		logging.error("Incorrect version of {} installed.".format(command_name))
		logging.error("{} versions compatible with SRST2 are ".format(command_name) + ", ".join(required_versions))
		exit(-1)

def get_bowtie_execs():
	'Return the "best" bowtie2 executables'

	exec_from_environment = os.environ.get('SRST2_BOWTIE2')
	if exec_from_environment and os.path.isfile(exec_from_environment):
		bowtie2_exec = exec_from_environment
	else:
		bowtie2_exec = None

	exec_from_environment = os.environ.get('SRST2_BOWTIE2_BUILD')
	if exec_from_environment and os.path.isfile(exec_from_environment):
		bowtie2_build_exec = exec_from_environment
	elif bowtie2_exec and os.path.isfile(bowtie2_exec+'-build'):
		bowtie2_build_exec = bowtie2_exec+'-build'
	else:
		bowtie2_build_exec = 'bowtie2-build'

	if bowtie2_exec is None:
		bowtie2_exec = 'bowtie2'

	return (bowtie2_exec, bowtie2_build_exec)

def bowtie_index(fasta_files):
	'Build a bowtie2 index from the given input fasta(s)'
	check_bowtie_version()
	for fasta in fasta_files:
		built_index = fasta + '.1.bt2'
		if os.path.exists(built_index):
			print 'Bowtie 2 index for {} is already built...'.format(fasta)
		else:
			print 'Building bowtie2 index for {}...'.format(fasta)
			run_command([get_bowtie_execs()[1], fasta, fasta])

def get_samtools_exec():
	'Return the "best" samtools executable'

	exec_from_environment = os.environ.get('SRST2_SAMTOOLS')
	if exec_from_environment and os.path.isfile(exec_from_environment):
		return exec_from_environment
	else:
		return 'samtools'

def samtools_index(fasta_files):
	'Build a samtools faidx index from the given input fasta(s)'
	check_samtools_version()
	for fasta in fasta_files:
		built_index = fasta + '.fai'
		if os.path.exists(built_index):
			print 'Samtools index for {} is already built...'.format(fasta)
		else:
			print 'Building samtools faidx index for {}...'.format(fasta)
			run_command([get_samtools_exec(), 'faidx', fasta])

def main():

	args = parse_args()

	if not args.rundir:
		args.rundir = os.getcwd()

	# parse list of file sets to analyse
	fileSets = read_file_sets(args) # get list of files to process

	# make sure the databases are formated for bowtie2 and samtools before running the jobs
	db = []
	m = re.search( r'(--mlst_db) (.*?) .*', args.other_args)
	if m != None:
		db.append(m.group(2))
	g = re.search( r'(--gene_db) (.*?) --', args.other_args)
	if g != None:
		db += g.group(2).split()
	else:
		g = re.search( r'(--gene_db) (.*?)$', args.other_args)
		if g != None:
			db += g.group(2).split()
	bowtie_index(db)
	samtools_index(db)

	# build and submit commands
	for sample in fileSets:
		cmd = "#!/bin/bash"
		cmd += "\n#$ -V"
		cmd += "\n#$ -cwd"
		cmd += "\n#$ -j y"
		cmd += "\n#$ -S /bin/bash"
		cmd += "\n#$ -N qsub_srst2"
		cmd += "\n#$ -q " +args.queue
		cmd += "\nmodule load srst2"
		cmd += "\ncd " + args.rundir
		cmd += "\nsrst2"
		fastq = fileSets[sample]
		if len(fastq) > 1:
			cmd += " --input_pe " + fastq[0] + " " + fastq[1]
			cmd += " --forward " + args.forward
			cmd += " --reverse " + args.reverse
		else:
			cmd += " --input_se " + fastq[0]
		cmd += " --output " + sample + "_" + args.output
		cmd += " --log"
		cmd += " " + args.other_args

		# print and run command
		print cmd
		echo_for_cmd = ["echo", "-e", "%s" % cmd] # we need this for the Popen pipe
		echocmdproc = subprocess.Popen(echo_for_cmd, stdout=subprocess.PIPE)
		out = subprocess.check_output("qsub", stdin=echocmdproc.stdout)
		echocmdproc.wait()
		# os.system('echo "' + cmd + '" | sbatch') # old slurm script command. Notice how and echo fot he command was also needed.

if __name__ == '__main__':
	main()
